59 
OTlVm—MONOGENEA, v. Ben. 
Family — Monocotylidce, Tschbg. 
Genus — CaUcotyJe, Diesing. 
Calicotyle kroyeri (Diesing). (Plate V., fig. 1.) Diesing, 
" Systema Helminthum," vol. I., page 419 (1850). 
This fine species inhabits the cloaca of the Starry Ray. I have 
always found it in females contrary to other observers, who 
generally record it from the males. I have sometimes seen it 
also in the uterus and once on the gills of the Starry Ray. It 
occurred in five specimens out of sixty examined, usually several 
in each fish. 
T. Scott * has recorded this species for Scotland from the Starry 
Ray, E. radiata, and also from R. clavata, and A. Scott | has found 
it in rays in the Irish Sea. Its morphology has been minutely 
investigated by Wierzejski.J 
The worm is white or pale yellowish, very much flattened dorso- 
ventrally, and bearing posteriorly on its ventral surface a circular 
disc with seven rays, and armed with two curved spines at the 
hind end, by the aid of which it attaches itself. The length of 
my specimens is about 4—5 mm., the breadth being slightly 
less than the length, and the shape of the body somewhat 
triangular. The anterior oral sucker is almost circular, and 
measures 070 mm. across; it has a circular opening leading to 
a muscular pharynx (0-40 mm. long), and there is a very small 
oesophagus branching into gracefully curved intestinal lobes which 
end just above the posterior disc. The excretory system follows 
closely the course of the intestine (outside it), and is very difficult 
to see. The testes are a large group of cells occupying the hind 
part of the space which is almost euclosed by the intestinal lobes; 
from them a vas deferens runs up the left side, curving round to 
the right just below the intestinal fork as a thin vesicula seminalis, 
ending blindly on the left and leading to a triangular bulbous 
cirrus sac with a curved and sharply pointed penis. The common 
genital pore or birth pore is in the middle line, a little way below 
the intestinal fork. The ovary and oviduct form a sinuous mass 
arising from the left side in front of the testes ; it runs trans- 
88 ai'Xf' T '' " Tvveutieih Annual R ^port of Fishery Board for Scotland." Part III, page 
Bct^fe1^^S ttt * tefc,,,4e,llSiaMB in ,he Irish Sca " Kept. Lanes. Sea Fish. 
th, U^5ySo mniSS d0S BaucS VOn Calico, - vIe Krp - veri Dies." Zeitseh. f. 
